1. Lymphatic system and body defenses
Nonspecific defenses
Do not distinguish one type of threat from another
7 types
Specific defenses
Protect against particular threats
Depend upon the activation of lymphocytes

2. SECTION 22-3 Nonspecific Defenses

3. Nonspecific Defenses, Physical barriers
Keep hazardous organisms outside the body
Includes hair, epithelia, secretions of integumentary and digestive systems

4. Figure 22.10 Nonspecific Defenses (Part 1 - Physical Barriers)

5. Nonspecific Defenses, Phagocytes
Remove cellular debris and respond to invasion by foreign pathogens
Monocyte-macrophage system - Fixed and free
Microphages – Neutrophils and eosinophils
Move by diapedesis
Exhibit chemotaxis

6. Figure 22.10 Nonspecific Defenses (Part 2 - Phagocytes)

7. Nonspecific Defenses, Immunological surveillance
Constant monitoring of normal tissue by NK cells
NK cells
Recognize cell surface markers on foreign cells
Destroy cells with foreign antigens

8. NK cell activation Recognition of unusual surface proteins
Rotation of the Golgi toward the target cell and production of perforins
Release of perforins by exocytosis
Interaction of perforins causing cell lysis

9. Figure 22.10 Nonspecific Defenses (Part 3 - Immunological Surveillance)

10. Figure 22.11 How Natural Killer Cells Kill Cellular Targets

11. Nonspecific Defenses, Interferons (cytokines)
Small proteins released by virally infected cells
Trigger the production of antiviral proteins
Three major types of interferons are:
Alpha– produced by leukocytes and attract/stimulate NK cells
Beta– secreted by fibroblasts causing slow inflammation
Gamma – secreted by T cells and NK cells stimulate macrophage activity

12. Figure 22.10 Nonspecific Defenses (Part 4 - Interferons)

13. Nonspecific Defenses, Complement system
Cascade of ~11 plasma complement proteins (C)
Destroy target cell membranes
Stimulate inflammation
Attract phagocytes
Enhance phagocytosis

14. Complement proteins interact with on another via two pathways
Classical
Alternative

15. Figure 22.10 Nonspecific Defenses (Part 5 - Complement System)

16. Figure 22.12 Complement Activation

17. Nonspecific Defenses, Inflammation
Localized tissue response to injury producing
Swelling
Redness
Heat
Pain
Effects of inflammation include
Temporary repair of injury
Slowing the spread of pathogens
Mobilization of local, regional, and systemic defenses

18. Figure 22.10 Nonspecific Defenses (Part 6 - Inflammatory Response)

19. Figure Inflammation
Figure 22.13

20. Nonspecific Defenses, Fever
Maintenance of a body temperature above 37.2oC (99oF)
Pyrogens reset the hypothalamic thermostat and raise body temperature
Pathogens, toxins, antigen-antibody complexes can act as pyrogens

21. Figure 22.10 Nonspecific Defenses (Part 7 - Fever)

22. SECTION 22-4 Specific Defenses

23. Forms of immunity Innate immunity Genetically determined
Present at birth
Acquired immunity
Not present at birth
Achieved by exposure to antigen
Active immunity
Passive immunity

24. Figure 22.14 Types of Immunity

25. Properties of immunity
Specificity – activated by and responds to a specific antigen
Versatility – is ready to confront any antigen at any time
Memory – “remembers” any antigen it has encountered
Tolerance – responds to foreign substances but ignores normal tissues

26. The immune system response
Antigen triggers an immune response
Activates T cells and B cells
T cells are activated after phagocytes exposed to antigen
T cells attack the antigen and stimulate B cells
Activated B cells mature and produce antibody
Antibody attacks antigen

27. Figure 22.15 An Overview of the Immune Response

28. SECTION 22-5 T cells and Cell-mediated Immunity

29. Major types of T cells Cytotoxic T cells (TC) – attack foreign cells
Helper T cells (TH) – activate other T cells and B cells
Suppressor T cells (TS) – inhibit the activation of T and B cells

30. Antigen presentation
Antigen-glycoprotein combination appears on a cell membrane
Called MHC proteins (Major Histocompatibility Complex)
Coded for by genes of the MHC
T-cells sensitive to the antigen are activated upon contact

31. MHC classes Class I – found on all nucleated cells
Class II – found on antigen presenting cells and lymphocytes

32. Lymphocytes respond to antigens bound to either class I or class II MHC proteins
Antigen recognition
T cell membranes contain CD markers
CD3 markers present on all T cells
CD8 markers on cytotoxic and suppressor T cells
CD4 markers on helper T cells

33. Figure 22.16 Antigens and MHC Proteins

34. Figure 22.16 Antigens and MHC Proteins

35. Figure 22.16 Antigens and MHC Proteins
Figure 22.16b

36. Activation of CD8 cells Responds quickly giving rise to other T cells
Cytotoxic T cells – seek out and destroy abnormal cells
lymphotoxin
Memory TC cells – function during a second exposure to antigen
Suppressor T cells – suppress the immune response

37. Figure 22.17 Antigen Recognition and the Activation of Cytotoxic T Cells

38. Figure 22.17 Antigen Recognition and the Activation of Cytotoxic T Cells
PLAY
Animation: Cytotoxic T Cell Activation
Figure 22.17

39. Activation of CD4 T cells by antigens presented on class II MHC proteins
Produces helper T cells and memory T cells
Activated helper T cells
Secrete lymphokines that coordinate specific and nonspecific defenses
Enhance nonspecific defenses
Stimulate the activity of NK cells
Promote activation of B cells

40. Figure 22.18 Antigen Recognition and Activation of Helper T cells
PLAY
Animation: Antigen Recognition and Helper T Cell Activation
Figure 22.18

41. Figure 22.19 A Summary of the Pathways of T Cell Activation

42. The Lymphatic System and Immunity
Chapter 22, part 4
The Lymphatic System and Immunity

43. SECTION 22-6 B Cells and Antibody-mediated Immunity

44. B cell sensitization of activation
Sensitization – the binding of antigens to the B cell membrane antibodies
Antigens then displayed on B cell Class II MHC
TH cells activated by same antigen stimulate B cell
Active B cell differentiates into Memory B Cell or Plasma cell
Plasma cells synthesize and release antibody

45. Figure 22.20 The Sensitization and Activation of B Cells
PLAY
Animation: B Cells and Antibody Production
Figure 22.20

46. Antibodies structure Antibodies are Y-shaped proteins consisting of:
Two parallel polypeptide chains
Heavy chains and light chains
Constant region and variable region
Antigen binding site

47. Figure 22.21 Antibody Structure

48. Figure 22.21 Antibody Structure

49. Figure 22.21 Antibody Structure
Figure 22.21b-d

50. Actions of antibodies include:
Neutralization
Agglutination and precipitation
Activation of complement
Attraction of phagocytes
Opsinization
Stimulation of inflammation
Prevention of adhesion

51. Classes of Antibodies (immunoglobins)
IgG – resistance against many viruses, bacteria and bacterial toxins
IgE – accelerates local inflammation
IgD – found on the surface of B cells
IgM – first type secreted after antigen arrives
IgA – primarily found in glandular sec

52. Primary and secondary antibody response
Primary response
Takes about two weeks to develop
Produced by plasma cells
Secondary response
Rapid increase in IgG
Maximum antibody titer app

53. Figure 22.22 The Primary and Secondary Immune Responses

54. Figure 22.23 An Integrated Summary of the Immune Response

55. Figure 22.25 The Course of the Body’s Response to Bacterial Infection
Figure 22.25a, b

56. SECTION 22-7 Normal and Abnormal Resistance

57. Development of the Immune Response
Immunological competence
The ability to demonstrate an immune response after exposure to an antigen
Fetuses receive immunity from the maternal bloodstream
Infants acquire immunity following exposure

58. Immune disorders Autoimmune disorders
Immune response mistakenly targets normal cells
Immunodeficiency diseases
Immune system does not develop properly or is blocked

59. Allergies Inappropriate or excessive immune response to allergens
Anaphylaxis
Circulating allergen affects mast cells throughout body

60. Figure 22.26 The Mechanism of Anaphylaxis

61. Stress and the immune response
Interleukin-1 released by active macrophages
Triggers release of ACTH resulting in glucocorticoid release
Moderates the immune response
Lowers resistance to disease

62. Stress can cause the following:
Depression of the inflammatory response
Phagocytic reduction
Inhibition of interleukin secretion

63. You should now be familiar with:
The structure and function of lymphatic cells, tissues and organs
The body’s nonspecific defenses and the components and mechanisms of each
Specific resistance, cell-mediated immunity and antibody mediated immunity
The role of the T cell, B cell and antibodies in specific immunity